1. Field of the Invention
The present invention relates to a pressure-sensitive adhesive label for a hard disk drive, which is used in a state that the pressure-sensitive adhesive label is stuck on the outer surface of a housing of a hard disk drive so as to exert a function of various indications as a primary function of a pressure-sensitive adhesive label and so as to reduce noise generated when the hard disk drive is driven.
2. Description of the Related Art
In recent years, there is a greatly increasing demand for civilian hard disk drives for use in personal computers and so on. Along with this demand, a property of miniaturization of the hard disk drive itself and a property of reduction in generated noise (securement of silence) at the time of driving of the hard disk drive have been treated to be as important as the property of increase in storage capacity.
As a measure to reduce noise generated when a hard disk drive is driven, a vibration damping steel sheet is generally used on a part (for example, a cover) of a housing of the hard disk drive. However, the method using a vibration damping steel sheet cannot yet be rated as a satisfactory measure from the point of view of reduction in size and weight, reduction in noise, productivity or cost particularly for a hard disk drive having recording disks each with a diameter not larger than 2.5 inches.
Therefore, the present inventor et al. proposed a pressure-sensitive adhesive label for a hard disk drive (hereinafter, occasionally referred to as “HDD pressure-sensitive adhesive label”) which was stuck on the outer surface of a housing of a hard disk drive so as to reduce noise generated when the hard disk drive was driven. By use of such an HDD pressure-sensitive adhesive label, reduction in noise can be attained while the information indication function is exerted. The HDD pressure-sensitive adhesive label has a pressure-sensitive adhesive layer normally coated (protected) with a release liner until the HDD pressure-sensitive adhesive label is used (stuck). When the HDD pressure-sensitive adhesive label is used, the release liner is released to expose the surface of the pressure-sensitive adhesive layer, and then the HDD pressure-sensitive adhesive label is stuck onto the outer surface of a housing of a hard disk drive.
On the other hand, a precision electronic apparatus such as a hard disk drive may be broken due to weak static electricity. Such a precision electronic apparatus is required to be prevented from being broken by static electricity.
In the HDD pressure-sensitive adhesive label, however, static electricity may be generated to cause peeling electrification when the release liner coating the pressure-sensitive adhesive layer is released from the HDD pressure-sensitive adhesive label. There is a possibility that a weak current generated at this time causes a failure in the precision electronic apparatus. Therefore, the HDD pressure-sensitive adhesive label is required to have a small amount of peeling electrification generated when the release liner is released.
Further, in the HDD pressure-sensitive adhesive label, however, damage such as curling in the HDD pressure-sensitive adhesive label as a whole or wrinkles produced therein comes into problem when the release liner coating the pressure-sensitive adhesive layer is released. It is therefore necessary to prevent such damage when the release liner is released. Further, when the HDD pressure-sensitive adhesive label in which the release liner has been released to expose the pressure-sensitive adhesive layer is to be stuck onto a hard disk drive, it is difficult to position the place where the HDD pressure-sensitive adhesive label is to be stuck on the hard disk drive because the pressure-sensitive adhesive layer has been exposed thoroughly. Accordingly, the workability in sticking the HDD pressure-sensitive adhesive label is low. Further, with weight reduction in the hard disk drive, reduction in thickness of the pressure-sensitive adhesive label is demanded accordingly. Along with this demand, it is anticipated that the pressure-sensitive adhesive label will be damaged easily when release liner is released. Thus, the solution to the problems is required more and more strongly.
On the other hand, in recent years, a product in which a hard disk drive has been incorporated, for example, various computer equipment such as a personal computer or a server or household appliances as a video/audio recording apparatus, are disassembled after retirement so that various parts are reused (recycled).
HDD pressure-sensitive adhesive labels are, however, stuck on hard disk drives manually or automatically by machines. For example, when a wrong HDD pressure-sensitive adhesive label is stuck, the HDD pressure-sensitive adhesive label has to be peeled after the sticking. Further, when hard disk drives are reused, HDD pressure-sensitive adhesive labels stuck on the hard disk drives have to be peeled. In spite of such increasing necessity to peel HDD pressure-sensitive adhesive labels which have been once stuck, it is difficult to peel, with ease, the related-art HDD pressure-sensitive adhesive labels after the HDD pressure-sensitive adhesive labels have been once stuck. Thus, there has occurred a problem that the workability in peeling the HDD pressure-sensitive adhesive labels is low. A requirement made on an HDD pressure-sensitive adhesive label is that the HDD adhesion label exhibiting adherence excellent enough not to be peeled easily when it is stuck, while the HDD pressure-sensitive adhesive label can be peeled easily when it has to be peeled.